Microbial metabolite enhances immunotherapy efficacy by modulating T cell stemness in pan-cancer.

The immune checkpoint blockade (ICB) response in human cancers is closely linked to the gut microbiota. Here, we report that the abundance of commensal Lactobacillus johnsonii is positively correlated with the responsiveness of ICB. Supplementation with Lactobacillus johnsonii or tryptophan-derived metabolite indole-3-propionic acid (IPA) enhances the efficacy of CD8+ T cell-mediated αPD-1 immunotherapy. Mechanistically, Lactobacillus johnsonii collaborates with Clostridium sporogenes to produce IPA. IPA modulates the stemness program of CD8+ T cells and facilitates the generation of progenitor exhausted CD8+ T cells (Tpex) by increasing H3K27 acetylation at the super-enhancer region of Tcf7. IPA improves ICB responsiveness at the pan-cancer level, including melanoma, breast cancer, and colorectal cancer. Collectively, our findings identify a microbial metabolite-immune regulatory pathway and suggest a potential microbial-based adjuvant approach to improve the responsiveness of immunotherapy.

Zic1 suppresses gastric cancer metastasis by regulating Wnt/ß-catenin signaling and epithelial-mesenchymal transition.

Gastric cancer (GC) patients with metastasis had limited treatment options and dismal outcome. We have previously reported the aberrant expression of Zic family member 1 (Zic1) in GC. However, the functional roles and underlying mechanism of Zic1 in GC metastasis remain unknown. Here, we demonstrate that lower expression of Zic1 was correlated with more lymph node metastasis and poor outcome of GC patients. Ectopic expression of Zic1 suppressed both lung metastasis and peritoneal tumor dissemination of GC in mice. The metastatic suppressing ability of Zic1 was mediated by regulating the process of cell invasion, adhesion and epithelial-mesenchymal transition (EMT). Mechanistically, Zic1 could downregulate Wnt targets including c-Myc and Cyclin D1 by inhibiting LEF transcriptional activity in GC cells. Notably, Zic1 was inversely related to the expression of Cyclin D1 in GC tissues tested. In addition, Zic1 could physically interact with ß-catenin/transcription factor 4 (TCF4) and disrupt their complex formation, while not affecting ß-catenin nuclear localization. Collectively, our study indicated that Zic1 suppressed GC metastasis through attenuating Wnt/ß-catenin signaling and the EMT process. Our work may provide novel therapeutic strategies for the metastasis of GC.

Variations in chemical fingerprints and major flavonoid contents from the leaves of thirty-one accessions of Hibiscus sabdariffa L.

The leaves of Hibiscus sabdariffa L. have been used as traditional folk medicines for treating high blood pressure and fever. There are many accessions of H. sabdariffa L. throughout the world. To assess the chemical variations of 31 different accessions of H. sabdariffa L., fingerprinting analysis and quantitation of major flavonoids were performed by high-performance liquid chromatography (HPLC). The HPLC method was validated for linearity, sensitivity, precision, repeatability and accuracy. A quadrupole-time-of-flight mass spectrometry (Q-TOF-MS) was applied for the characterization of major compounds. A total of 9 compounds were identified, including 6 flavonoids and 3 phenolic acids. In the fingerprint analysis, similarity analysis (SA) and principal component analysis (PCA) were used to differentiate the 31 accessions of H. sabdariffa L. Based on the results of PCA and SA, the samples No. 15 and 19 appeared much different from the main group. The total content of five flavonoids varied greatly among different accessions, ranging from 3.35 to 23.30 mg/g. Rutin was found to be the dominant compound and the content of rutin could contribute to chemical variations among different accessions. This study was helpful to understand the chemical variations between different accessions of H. sabdariffa L., which could be used for quality control. © 2015 The Authors Biomedical Chromatography Published by John Wiley & Sons Ltd.

Antioxidant activity of leaf extracts from different Hibiscus sabdariffa accessions and simultaneous determination five major antioxidant compounds by LC-Q-TOF-MS.

Hibiscus sabdariffa has gained attention for its antioxidant activity. There are many accessions of H. sabdariffa in the world. However, information on the quantification of antioxidant compounds in different accessions is rather limited. In this paper, a liquid chromatography/quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS) method for simultaneous determination of five antioxidant compounds (neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, rutin, and isoquercitrin) in H. sabdariffa leaves was developed. The method was validated for linearity, sensitivity, precision, repeatability and accuracy. The validated method has been successfully applied for determination of the five analytes in eight accessions of H. sabdariffa. The eight accessions of H. sabdariffa were evaluated for their antioxidant activities by DPPH free radical scavenging assay. The investigated accessions of H. sabdariffa were rich in rutin and exhibited strong antioxidant activity. The two accessions showing the highest antioxidant activities were from Cuba (No. 2) and Taiwan (No. 5). The results indicated that H. sabdariffa leaves could be considered as a potential antioxidant source for the food industry. The developed LC-Q-TOF-MS method is helpful for quality control of H. sabdariffa.

L-arginine metabolism ameliorates age-related cognitive impairment by Amuc_1100-mediated gut homeostasis maintaining.

Aging-induced cognitive impairment is associated with a loss of metabolic homeostasis and plasticity. An emerging idea is that targeting key metabolites is sufficient to impact the function of other organisms. Therefore, more metabolism-targeted therapeutic intervention is needed to improve cognitive impairment. We first conducted untargeted metabolomic analyses and 16S rRNA to identify the aging-associated metabolic adaption and intestinal microbiome change. Untargeted metabolomic analyses of plasma revealed L-arginine metabolic homeostasis was altered during the aging process. Impaired L-arginine metabolic homeostasis was associated with low abundance of intestinal Akkermansia muciniphila (AKK) colonization in mice. Long-term supplementation of AKK outer membranes protein-Amuc_1100, rescued the L-arginine level and restored cognitive impairment in aging mice. Mechanically, Amuc_1100 acted directly as a source of L-arginine and enriched the L-arginine-producing bacteria. In aged brain, Amuc_1100 promoted the superoxide dismutase to alleviated oxidation stress, and increased nitric oxide, derivatives of L-arginine, to improve synaptic plasticity. Meanwhile, L-arginine repaired lipopolysaccharide-induced intestinal barrier damage and promoted growth of colon organoid. Our findings indicated that aging-related cognitive impairment was closely associated with the disorders of L-arginine metabolism. AKK-derived Amuc_1100, as a potential postbiotic, targeting the L-arginine metabolism, might provide a promising therapeutic strategy to maintain the intestinal homeostasis and cognitive function in aging.

Bifidobacterium adolescentis induces Decorin+ macrophages via TLR2 to suppress colorectal carcinogenesis.

BACKGROUND: The interplay between gut microbiota and tumor microenvironment (TME) in the pathogenesis of colorectal cancer (CRC) is largely unknown. Here, we elucidated the functional role of B. adolescentis and its possible mechanism on the manipulation of Decorin+ macrophages in colorectal cancer. METHODS: The relative abundance of B. adolescentis in tumor or para-tumor tissue of CRC patients was analyzed. The role of B. adolescentis was explored in the CRC animal models. The single cell-RNA sequencing (scRNA-seq) was used to investigate the myeloid cells subsets in TME. The expression level of TLR2/YAP axis and its downstream Decorin in macrophages were tested by Western blot and qRT-PCR. Knockdown of Decorin in Raw264.7 was performed to investigate the effect of Decorin+ macrophages on subcutaneous tumor formation. Multi-immunofluorescence assay examined the number of Decorin+ macrophages on the CRC tissue. RESULTS: We found that the abundance of B. adolescentis was significantly reduced in tumor tissue of CRC patients. Supplementation with B. adolescentis suppressed AOM/DSS-induced tumorigenesis in mice. ScRNA-seq and animal experiment revealed that B. adolescentis increased Decorin+ macrophages. Mechanically, Decorin was activated by TLR2/YAP axis in macrophages. The abundance of B. adolescentis was correlated with the number of Decorin+ macrophages and the expression level of TLR2 in tumor tissue of CRC patients. CONCLUSIONS: These results highlight that B. adolescentis induced Decorin+ macrophages and provide a novel therapeutic target for probiotic-based modulation of immune microenvironment in CRC.

Bifidobacterium adolescentis orchestrates CD143+ cancer-associated fibroblasts to suppress colorectal tumorigenesis by Wnt signaling-regulated GAS1.

BACKGROUND: The interplay between gut microbiota and tumor microenvironment (TME) in the pathogenesis of colorectal cancer (CRC) is not well explored. Here, we elucidated the functional role of Bifidobacterium adolescentis (B.a) on CRC and investigated its possible mechanism on the manipulation of cancer-associated fibroblasts (CAFs) in CRC. METHODS: Different CRC animal models and various cell line models were established to explore the function of B.a on CRC. The single-cell RNA sequencing (scRNA-seq) or flow cytometry was used to detect the cell subsets in the TME of CRC. Western blot, quantitative real-time polymerase chain reaction (qRT-PCR), or immunofluorescence staining were performed to examine the activation of Wnt signaling and growth arrest specific 1 (GAS1) on CD143+ CAFs. Chromatin immunoprecipitation quantitative real-time PCR (CHIP-qPCR) was performed to investigate the regulation of transcription factor 4 (TCF4) on GAS1. Multi-immunofluorescence assay examined the expression level of CD143 and GAS1 on tissue microarray. RESULTS: We found that B.a abundance was significantly reduced in CRC patients from two independent cohorts and the bacteria database of GMrepo. Supplementation with B.a suppressed ApcMin/+ spontaneous or AOM/DSS-induced tumorigenesis in mice. scRNA-seq revealed that B.a facilitated a subset of CD143+ CAFs by inhibiting the infiltration of Th2 cells, while promoting the TNF-alpha+ B cells in TME. CD143+ CAFs highly expressed GAS1 and exhibited tumor suppressive effect. Mechanistically, GAS1 was activated by the Wnt/ß-catenin signaling in CD143+ CAFs. B.a abundance was correlated with the expression level of CD143 and GAS1. The level of CD143+ CAFs predicted the better survival outcome in CRC patients. CONCLUSIONS: These results highlighted that B.a induced a new subset of CD143+ CAFs by Wnt signaling-regulated GAS1 to suppress tumorigenesis and provided a novel therapeutic target for probiotic-based modulation of TME in CRC.

Heat-inactivated Bifidobacterium adolescentis ameliorates colon senescence through Paneth-like-cell-mediated stem cell activation.

Declined numbers and weakened functions of intestinal stem cells (ISCs) impair the integrity of the intestinal epithelium during aging. However, the impact of intestinal microbiota on ISCs in this process is unclear. Here, using premature aging mice (telomerase RNA component knockout, Terc-/-), natural aging mice, and in vitro colonoid models, we explore how heat-inactivated Bifidobacterium adolescentis (B. adolescentis) affects colon senescence. We find that B. adolescentis could mitigate colonic senescence-related changes by enhancing intestinal integrity and stimulating the regeneration of Lgr5+ ISCs via Wnt/ß-catenin signaling. Furthermore, we uncover the involvement of Paneth-like cells (PLCs) within the colonic stem-cell-supporting niche in the B. adolescentis-induced ISC regeneration. In addition, we identify soluble polysaccharides (SPS) as potential effective components of B. adolescentis. Overall, our findings reveal the role of heat-inactivated B. adolescentis in maintaining the ISCs regeneration and intestinal barrier, and propose a microbiota target for ameliorating colon senescence.

Lactobacillus Intestinalis Primes Epithelial Cells to Suppress Colitis-Related Th17 Response by Host-Microbe Retinoic Acid Biosynthesis.

Gut microbiome is integral to the pathogenesis of ulcerative colitis. A novel probiotic Lactobacillus intestinalis (L. intestinalis) exerts a protective effect against dextran sodium sulfate-induced colitis in mice. Based on flow cytometry, colitis-associated Th17 cells are the target of L. intestinalis, which is supported by the lack of protective effects of L. intestinalis in T cell-null Rag1-/- mice or upon anti-IL-17-A antibody-treated mice. Although L. intestinalis exerts no direct effect on T cell differentiation, it decreases C/EBPA-driven gut epithelial SAA1 and SAA2 production, which in turn impairs Th17 cell differentiation. Cometabolism of L. intestinalis ALDH and host ALDH1A2 contributed to elevated biosynthesis of retinoic acid (RA), which accounts for the anti-colitis effect in RAR-α -mediated way. In a cohort of ulcerative colitis patients, it is observed that fecal abundance of L. intestinalis is negatively associated with the C/EBPA-SAA1/2-Th17 axis. Finally, L. intestinalis has a synergistic effect with mesalazine in alleviating murine colitis. In conclusion, L. intestinalis and associated metabolites, RA, have potential therapeutic effects for suppressing colonic inflammation by modulating the crosstalk between intestinal epithelia and immunity.

Asymmetric flow field-flow fractionation with multiangle light scattering detection for characterization of cellulose nanocrystals.

Cellulose nanocrystals (CNCs) were analyzed by asymmetric flow field-flow fractionation (AF4) coupled with multiangle light scattering (MALS) detection. Small fractions were collected from the output of the AF4 apparatus for investigation by transmission electron microscopy (TEM). The influence of CNC injection amount, the number of passes through a high-pressure homogenizer, and different CNC sources on the elution behavior and particle size distribution was investigated. The AF4-MALS results on crystal length were compared with those from TEM. Peak distortion and variation in elution profiles with the increase in sample load were observed. Good resolution was obtained when the injection mass varied from 20 to 40 µg, corresponding to injections of 4-8 µL at a starting concentration of ~5 µg/µL; concentrations during the separation process and at the detector were significantly lower. As the number of homogenization treatments increased, the peak shape became narrower and more symmetrical. This indicates a narrowed crystal length distribution, but regardless of source or homogenization treatment, no CNC preparation was as uniform as tobacco mosaic virus, a well-known rigid rod model structure, whose length was found by AF4-MALS to be in agreement with literature values. CNCs derived from cotton contained longer crystals than those derived from microcrystalline cellulose, as shown by both AF4-MALS and TEM techniques. An advantage of AF4-MALS compared to TEM is the ability to sample large numbers of rodlike particles, which is challenging and time-consuming for TEM image analysis, especially without the presorting afforded by AF4. The good TMV results suggest a high degree of accuracy will pertain to the CNC size distribution measurements.

Distribution and characterization of extrachromosomal circular DNA in colorectal cancer.

Extrachromosomal circular DNA (eccDNA) has been shown to play an important role in the amplification of tumor genes and the maintenance of intra-tumor genetic heterogeneity, although its complex functional mechanism still remains to be elucidated. As the top three common malignancies in the world, colorectal cancer (CRC) has been threatening human life and health, whose tumorigenesis and development may have elusive connection with eccDNAs. Here, we described the extensive distribution of eccDNAs in the CRC tissues using Circle-seq, which range in size from hundreds to thousands of base pairs (bp). The distribution in tumor tissues had aggregation and tendency compared with random in tumor-adjacent tissues, accompanied with smaller and more regular circle lengths. After sequencing and restoring, we found that the shedding sites of eccDNAs in CRC had similar tendency in chromosome distribution, and focused on tumor-associated genes. Meanwhile, we combined RNA sequencing to explore the correlation of eccDNA differential expression in the gene transcription and signaling pathways, confirming a connection between eccDNA and RNA somewhere. Subsequently, we validated eccDNAs in CRC cell lines and the potential consistency of the junction sites of eccDNAs in CRC tissues and cell lines. Using fragments of the cationic amino acid transporter SLC7A1 to synthesize eccDNAs, we discovered the role of eccDNAs in different regions within the gene.

Fusobacterium nucleatum promotes colorectal cancer cells adhesion to endothelial cells and facilitates extravasation and metastasis by inducing ALPK1/NF-κB/ICAM1 axis.

Metastasis is the leading cause of death for colorectal cancer (CRC) patients, and the spreading tumor cells adhesion to endothelial cells is a critical step for extravasation and further distant metastasis. Previous studies have documented the important roles of gut microbiota-host interactions in the CRC malignancy, and Fusobacterium nucleatum (F. nucleatum) was reported to increase proliferation and invasive activities of CRC cells. However, the potential functions and underlying mechanisms of F. nucleatum in the interactions between CRC cells and endothelial cells and subsequent extravasation remain unclear. Here, we uncovered that F. nucleatum enhanced the adhesion of CRC cells to endothelial cells, promoted extravasation and metastasis by inducing ICAM1 expression. Mechanistically, we identified that F. nucleatum induced a new pattern recognition receptor ALPK1 to activate NF-κB pathway, resulting in the upregulation of ICAM1. Interestingly, the abundance of F. nucleatum in tumor tissues of CRC patients was positively associated with the expression levels of ALPK1 and ICAM1. Moreover, high expression of ALPK1 or ICAM1 was significantly associated with a shorter overall survival time of CRC patients. This study provides a new insight into the role of gut microbiota in engaging into the distant metastasis of CRC cells.

Stem cell-homing hydrogel-based miR-29b-5p delivery promotes cartilage regeneration by suppressing senescence in an osteoarthritis rat model.

Osteoarthritis (OA) is a common joint disease characterized by progressive loss of cartilage and reduction in lubricating synovial fluid, which lacks effective treatments currently. Here, we propose a hydrogel-based miRNA delivery strategy to rejuvenate impaired cartilage by creating a regenerative microenvironment to mitigate chondrocyte senescence that mainly contributes to cartilage breakdown during OA development. An aging-related miRNA, miR-29b-5p, was first found to be markedly down-regulated in OA cartilage, and their up-regulation suppressed the expression of matrix metalloproteinases and senescence-associated genes (P16INK4a/P21) via ten-eleven-translocation enzyme 1 (TET1). An injectable bioactive self-assembling peptide nanofiber hydrogel was applied to deliver agomir-29b-5p, which was functionalized by conjugating a stem cell-homing peptide SKPPGTSS for endogenous synovial stem cell recruitment simultaneously. Sustained miR-29b-5p delivery and recruitment of synovial stem cells and their subsequent differentiation into chondrocytes led to successful cartilage repair and chondrocyte rejuvenation. This strategy enables miRNA-based therapeutic modality to become a viable alternative for surgery in OA treatment.

Lactobacillus johnsonii alleviates colitis by TLR1/2-STAT3 mediated CD206+ macrophagesIL-10 activation.

Imbalance of gut microbiota homeostasis is related to the occurrence of ulcerative colitis (UC), and probiotics are thought to modulate immune microenvironment and repair barrier function. Here, in order to reveal the interaction between UC and gut microbiota, we screened a new probiotic strain by 16S rRNA sequencing from Dextran Sulfate Sodium (DSS)-induced colitis mice, and explored the mechanism and clinical relevance. Lactobacillus johnsonii (L. johnsonii), as a potential anti-inflammatory bacterium was decreased colonization in colitis mice. Gavage L. johnsonii could alleviate colitis by specifically increasing the proportion of intestinal macrophages and the secretion of Il-10 with macrophages depleted model and in Il10-/- mice. We identified this subset of immune cells activated by L. johnsonii as CD206+ macrophagesIL-10. Mechanistically, L. johnsonii supplementation enhanced the mobilization of CD206+ macrophagesIL-10 through the activation of STAT3 in vivo and in vitro. In addition, we revealed that TLR1/2 was essential for the activation of STAT3 and the recognition of L. johnsonii by macrophages. Clinically, there was positive correlation between the abundance of L. johnsonii and the expression level of MRC1, IL10 and TLR1/2 in UC tissues. L. johnsonii could activate native macrophages into CD206+ macrophages and release IL-10 through TLR1/2-STAT3 pathway to relieve experimental colitis. L. johnsonii may serve as an immunomodulator and anti-inflammatory therapeutic target for UC.

The Aged Intestine: Performance and Rejuvenation.

Owing to the growing elderly population, age-related problems are gaining increasing attention from the scientific community. With senescence, the intestine undergoes a spectrum of changes and infirmities that are likely the causes of overall aging. Therefore, identification of the aged intestine and the search for novel strategies to rescue it, are required. Although progress has been made in research on some components of the aged intestine, such as intestinal stem cells, the comprehensive understanding of intestinal aging is still limited, and this restricts the in-depth search for efficient strategies. In this concise review, we discuss several aspects of intestinal aging. More emphasis is placed on the appraisal of current and potential strategies to alleviate intestinal aging, as well as future targets to rejuvenate the aged intestine.

Akkermansia muciniphila Alleviates Dextran Sulfate Sodium (DSS)-Induced Acute Colitis by NLRP3 Activation.

Akkermansia muciniphila has been proved to play a crucial role in the progression of colitis, but its underlying mechanism remains inconclusive. In this study, we aim to investigate the effect of A. muciniphila on the development of acute colitis and explore the underlying mechanism. We found that the fecal level of A. muciniphila was decreased in ulcerative colitis (UC) patients compared to the healthy people in the GMrepo database. Oral administration of A. muciniphila strain BAA-835 significantly ameliorated the symptoms in dextran sulfate sodium (DSS)-induced acute colitis, evidenced by decreased body weight loss, colon length shortening, and colon histological inflammatory score. In addition, the number of goblet cells and the mucin family were enhanced after A. muciniphila treatment. Furthermore, proinflammatory cytokines such as tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and monocyte chemoattractant protein 1 (MCP-1) had a downward trend. Mechanistically, the expression of NLRP3, caspase-1 p20, and IL-1ß p17 were upregulated in A. muciniphila-treated mice. Additionally, the colon tissues from high-A. muciniphila UC patients had a higher NLRP3 expression than that from low-A. muciniphila UC patients. Moreover, the upregulation of NLRP3 was observed in mouse macrophage Raw264.7 cells and bone marrow-derived macrophage (BMDM) cells after incubation with A. muciniphila. To clarify whether the protective effect of A. muciniphila in colitis depends on NLRP3, we performed the NLRP3-deficient assay in NLRP3-/- mice in vivo. The evidence showed that NLRP3 deficiency eliminated the protective effects of A. muciniphila in acute colitis. In conclusion, A. muciniphila alleviates DSS-induced acute colitis by NLRP3 activation, which enriches the mechanism and provides a new prospect for the probiotic-based treatment of colitis. IMPORTANCE The gut microbiota and host immune response interaction influences the progression of intestinal inflammatory disease. As a well-recognized next-generation probiotic, Akkermansia muciniphila has been proved to play a crucial role in the progression of colitis, but its underlying mechanism remains inconclusive. We found that oral administration of A. muciniphila strain BAA-835 significantly ameliorated the symptoms of acute colitis. Mechanistically, the expression of NLRP3 was upregulated in the A. muciniphila group, and the protective effect of A. muciniphila in colitis depends on NLRP3 activation. This enriches the mechanism and provides a new prospect for the probiotic-based treatment of colitis, which would promote a deeper understanding of the complex characteristics of A. muciniphila and provide guidance for the treatment of human colitis in the future.

B. adolescentis ameliorates chronic colitis by regulating Treg/Th2 response and gut microbiota remodeling.

Inflammatory bowel disease (IBD) is defined as an immune dysregulation disease with poor prognosis. Various therapies based on gut microbe modulation have been proposed. In this study, we aim to explore the therapeutic effect of B. adolescentis on IBD, as well as the immune and microecology mechanism of B. adolescentis in IBD. The fecal level of B. adolescentis was decreased in the IBD patients compared with the normal people in our cohort and the GMrepo database. To further clarify the role of B. adolescentis in IBD, we induced chronic colitis with three cycles of dextran sulfate sodium (DSS). We found B. adolescentis gavage exhibited protective effects as evidenced by the significantly decreased diarrhea score, spleen weight, and increased colon length. Accordingly, the cumulative histological grading was decreased in the B. adolescentis administration group. In addition, tight junction protein and mucin family were enhanced after B. adolescentis treatment. Furthermore, distinct effects were found with decreased pro-inflammatory cytokines such as TNF-α, IL-6, IL-1ß, IL-18, IL-22, IL-9 and increased anti-inflammatory cytokines IL-10, IL-4, IL-5. Importantly, the colon lamina propria in the B. adolescentis group consisted of more Treg and Th2 cells, which inhibited extreme gut inflammation. Additionally, 16srRNA sequencing showed an evident increase in the B:F ratio in the B. adolescentis group. In particular, B. adolescentis application inhibited the excessive growth of Akkermansia and Escherichia-Shigella in genus level. In conclusion, B. adolescentis refined the DSS-induced chronic colitis by stimulating protective Treg/Th2 response and gut microbiota remodeling. B. adolescentis regularly treatment might improve the therapeutic effects for inflammatory bowel disease.

Fusobacterium nucleatum promotes colorectal cancer metastasis through miR-1322/CCL20 axis and M2 polarization.

Colorectal cancer (CRC) is one of the most common malignant tumors and is associated with Fusobacterium nucleatum (F. nucleatum, Fn) infection. In this study, we explored the role of F. nucleatum in the CRC metastasis. Our results showed that the abundance of F. nucleatum was enriched in the feces and tumors of patients with CRC and tended to increase in stage IV compared to stage I in patients with metastatic CRC. Tumor-derived CCL20 activated by F. nucleatum not only increases CRC metastasis, but also participates in the reprograming of the tumor microenvironment. F. nucleatum promoted macrophage infiltration through CCL20 activation and simultaneously induced M2 macrophage polarization, enhancing the metastasis of CRC. In addition, we identified using database prediction and luciferase activity hat miR-1322, a candidate regulatory micro-RNA, could bind to CCL20 directly. F. nucleatum infection decreased the expression of miR-1322 by activating the NF-κB signaling pathway in CRC cells. In conclusion, F. nucleatum promotes CRC metastasis through the miR-1322/CCL20 axis and M2 polarization.

Micropeptide ASAP encoded by LINC00467 promotes colorectal cancer progression by directly modulating ATP synthase activity.

Emerging evidence has shown that open reading frames inside long noncoding RNAs (lncRNAs) could encode micropeptides. However, their roles in cellular energy metabolism and tumor progression remain largely unknown. Here, we identified a 94 amino acid-length micropeptide encoded by lncRNA LINC00467 in colorectal cancer. We also characterized its conservation across higher mammals, localization to mitochondria, and the concerted local functions. This peptide enhanced the ATP synthase construction by interacting with the subunits α and γ (ATP5A and ATP5C), increased ATP synthase activity and mitochondrial oxygen consumption rate, and thereby promoted colorectal cancer cell proliferation. Hence, this micropeptide was termed ATP synthase-associated peptide (ASAP). Furthermore, loss of ASAP suppressed patient-derived xenograft growth with attenuated ATP synthase activity and mitochondrial ATP production. Clinically, high expression of ASAP and LINC00467 predicted poor prognosis of colorectal cancer patients. Taken together, our findings revealed a colorectal cancer-associated micropeptide as a vital player in mitochondrial metabolism and provided a therapeutic target for colorectal cancer.

A. Muciniphila Suppresses Colorectal Tumorigenesis by Inducing TLR2/NLRP3-Mediated M1-Like TAMs.

The interplay between gut microbiota and the host immune system is emerging as a factor in the pathogenesis of colorectal cancer. Here, we set out to identify the effect of Akkermansia muciniphila (A. muciniphila) on colorectal cancer pathogenesis. A. muciniphila abundance was significantly reduced in patients with colorectal cancer from two independent clinical cohorts and the GMrepo dataset. Supplementation with A. muciniphila suppressed colonic tumorigenesis in ApcMin/+ mice and the growth of implanted HCT116 or CT26 tumors in nude mice. Mechanistically, A. muciniphila facilitated enrichment of M1-like macrophages in an NLRP3-dependent manner in vivo and in vitro. As a consequence, NLRP3 deficiency in macrophages attenuated the tumor-suppressive effect of A. muciniphila. In addition, we revealed that TLR2 was essential for the activation of the NF-κB/NLRP3 pathway and A. muciniphila induced M1-like macrophage response. We observed positive correlations between M1-like macrophages, NLRP3/TLR2 and A. muciniphila in patients with colorectal cancer, which corroborated these findings. In summary, A. muciniphila-induced M1-like macrophages provide a therapeutic target in the colorectal cancer tumor microenvironment.